There's no such thing as a class with no constructor, if you don't provide a private one with no arguments, a public one is created. Otherwise, what the other guy said ( factory patterns, etc ). One common use for this would be for a single instance only to exist of a class, so you have a private constructor, in a static class, which has a property that returns the only possible instance of itself. Good for settings, for example.
Christian Graus Driven to the arms of OSX by Vista.